Water cooled vacuum tube



1936- l. E. MOUROMTSEFF ET AL 6 'WATER COOLED VACUUM V'I'UBE Filed Feb. 6, 1932 WITNESSES:

mf E mzw NW N i 2 nd Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE WATER COOLED VACUUM TUBE Application February 6, 1932, Serial No. 591,338

7 Claims.

Our invention relates to vacuum tubes and particularly to transmitter tubes having water-cooling jackets.

In high-power transmitter tubes, the anode 5 usually forms part of the vacuum tube envelope and is surrounded by a water-cooling jacket, a fiow of water being maintained between the anode and the jacket. When this structure is employed, a rapid fiow of water is desired in order to dis- 10 sipate the heat, and, in order that the water may be passed through the cooling jacket at a high velocity without utilizing too great a volume of water, the spacing between the anode and the inner surface of the cooling jacket is made very 5 small.

An object of our invention is to provide means for so directing the flow of water in the abovementioned small spacing that more efiicient cooling will be obtained.

20 .A further object of our invention is to provide a structure in which the close fitting tubular casing around the anode shall always be spaced from the anode a certain amount.

In practicing our invention we form longitudi- 25 nal ribs on the anode and surround it with a metallic tube which is split in order thatit may be slipped over a seal in the envelope. The split tube is supported directly from the anode by means of metallic supports or feet. A solid tube,

30 which forms a portion of a water-tight chamber,

is closely fitted over the split tube.

The longitudinal ribs on the anode are provided for the main purpose of so directing the flow of water that maximum cooling of the anode is ob- 35 tained.

Other features and advantages of our invention will appear from the following description taken in connection with the accompanying drawing, in which:

40 Figure 1 is a longitudinal section of a portion of a vacuum tube envelope and of a cooling jacket constructed in accordance with our invention.

Fig, 2 is an enlarged view taken on the line 11-11 of Fig. 1, and

5 Fig. 3 is an enlarged view in elevation of the split tube.

Referring to Fig. 1, the vacuum tube comprises an envelope which consists of a metallic anode I I having a glass blank I2 sealed to it at one end 5 and a glass blank I3 sealed to the other end. The filament and control electrodes are not shown in Fig. 1 for the sake of clearness but are illustrated in Fig. 2. The complete tube, with the exception of our improved form of cooling jacket, is shown .55 in application Serial No. 344,772, filed March 6,

1929, now Patent No. 1,944,190 issued January 23, 1934, in the name of Ilia E. Mouromtseff, and application Serial No. 358,608, filed April 27, 1929, now Patent No. 1,973,094 issued September 11, 1934, in the name of Ilia E. Mouromtseif and Gregory V. Rylsky, both applications being assigned to the Westinghouse Electric 8: Manufacturing Company. The cooling jacket disclosed in these figures constitutes an improvement on the cooling jacket disclosed in our copending applica- 10 tion, Serial No. 227,425, filed October 20, 1927 for Vacuum tubes, now Patent No. 1,971,988 issued August 28, 1934. The cooling jacket disclosed in these figures constitutes an improvement on the cooling jacket disclosed in our copending application, Serial No. 227,425, filed October 20, 1927 for Vacuum tubes.

In accordance with our invention the anode I I is provided with longitudinal ribs III and with a close fitting cooling jacket I I. This structure causes'the water to flow in substantially straight lines along the longitudinal axis of the tube. The ribs I0 make it impossible for the jacket I to come into contact with the anode II, in which case the cooling liquid would fail to reach a portion of the anode.

The cooling jacket cylinder I 4, which is split to make it flexible, is slipped over the anode II and is supported directly from the anode II by m'eans of metallic feet I5 bolted, or otherwise secured, to the cylinder I. The split cylinder I I is held in position by wrapping wire I6 around the anode II and feet I5.

The manner in which the cylinder I4 is split will be seen by referring to Fig. 3. On the under side of the cylinder, a saw cut I'I extends the entire length of the cylinder. On the upper side of the cylinder I4, two saw cuts I8 and I9 extend for only a portion of its length. In this manner, the cylinder is made flexible enough, so that its 40 diameter may be increased sufiiciently to permit slipping the cylinder over the seal 20. After the cylinder has been slipped over the seal 20 and around the anode I I, it springs back to its original diameter to form a very close spacing between its inner surface and the outer surface of the anode.

The split cylinder I4 is entirely surrounded by a water-tight cooling jacket. This jacket comprises a water-tight cylinder 2I with an internal diameter that is larger than the external diam- 5 eter of the seal 20. The cylinder 2I fits snugly over the split cylinder I4. At one end, it issecured to an annular member 22 by means of a flexible diaphragm 23. In practice, the diaphragm 23 is made of inch soft copper. The

Cir

annular member 22 is supported on the anode II by means of a one piece ring 2% threaded on the anode.

A gasket is positioned between a split ring 21 and the ring 24 and may be compressed by means of a plurality of pivoted hooks 28. The hooks are pivoted on the head of a screw 25 as indicated by the broken lines. In order to compress the gasket 25, either the screw 25 is turned or the screw 29 is turned to lift the end of the hook away from the annular member 22.

The other end of the cylinder 25 is likewise secured to an annular member 38 by means of a flexible diaphragm 3! similar to diaphragm 23. A gasket 32 and a split ring 33 are positioned between the annular member and a split ring 34. Openings 35 and 36 are provided in the annular members to provide an inlet and outlet for the cooling liquid.

The cooling jacket is firmly supported on the anode H by attaching the feet l5 thereto and wiring them on the anode.

The cooling jacket structure comprising the members 2|, 22, 23, 30 and 3! is clamped on a bench with the member 30 at the bottom. The split ring 2'! and gasket 25 are then placed in member 22. The anode H, with split cylinder i4 and members l2 and i3 attached, is slipped downward to fit in the outer jacket members as shown. The gasket 26 is then compressed to form a water-tight joint.

Next, the above-described complete assembly is turned upside down and clamped on a bench with member 22 at the bottom. The split rings 33 and 34 and the gasket 32 are placed in position and the gasket 32 is compressed in the same manner as the gasket at the opposite end.

It will be noted that this structure has a decided advantage over that in which the cooling jacket cylinder adjacent to the anode is supported from annular rings such as 22 and 3E, because it is difficult to so mount the annular rings that the spacing between the cooling jacket cylinder and the anode is small and accurate. The flexible diaphragms 23 and 3| are provided in order to prevent undesirable strains in the tube structure caused either by the unequal expansion of the anode and the water cooling cy1 inder during the operation of the tube or by the anode and cooling jacket getting out of alignment.

In operation, the tube is set in a vertical position and water is passed into the bottom of the cooling jacket at sufiicient pressure to force the water along the anode at a high velocity. The water then flows out of the cooling jacket through the annular member at the top of the jacket.

The longitudinal ribs I!) prevent eddy currents from forming in a direction lateral to the main flow of the cooling liquid. At the same time, they aid the formation of eddy currents in the liquid in a direction parallel to the longitudinal axis of the tube and these eddy currents assist in cooling the anode since they move the liquid from the anode surface to the cooling jacket surface.

While the ribs Ii] increase the radiating surface of the anode a certain amount, their main function is to direct the flow of liquid and to prevent contact between the cooling jacket and anode surface H as explained above.

It is important that there be a close spacing between the anode ii and the cooling jacket id as, otherwise, the addition of ribs to the anode will reduce the cooling effect of the liquid in spite of the increased radiating surface. This reduction in cooling will be a result of the decreased velocity of the liquid flow at the anode surface caused by the resistance to liquid flow introduced by the ribs. If the space between anode and jacket is very small, however, the liquid in contact with the anode surface is forced to travel at approximately the same high velocity as the body of Water nearer the cooling jacket.

In the example of my invention illustrated in the drawing, the outer diameter of the anode H was 4.14 inches, the height of the ribs ID was .055 inch, the length of the ribs [0 was approximately 19 inches, and the spacing between the top of the ribs l0 and the inner surface of the cooling jacket l4 was .04 inch.

The spacing between adjacent ribs is sufficient to allow a flow of water that will cool the anode even though the jacket i4 comes into contact with the ribs.

It may be noted that there is an advantage in putting ribs on the anode which is independent of their cooling-function. During the heat treatment process for securing a proper degree of evacuation in the tube, the anode is softened to such an extent that with a smooth surface anode there is danger of the anode collapsing. The ribs strengthen the anode so that this danger of collapse is greatly reduced.

In Fig. 2 are illustrated the cathodes 4'! and the disk grid 44 supported on a tube 45. The specific structure of these cooperating electrodes is more fully disclosed in our copending application, Serial No. 358,608, above referred to. Practically any type of cathode and grid suitable for these tubes, however, may be used, since the invention disclosed in this present application is not limited to any of these types of cathode and grid.

Various modifications may be made in our invention without departing from the spirit and scope thereof, and we desire, therefore, that only such limitations shall be placed thereon as are shown by the prior art and are set forth in the appended claims.

We claim as our invention:

1. A cooling system for an electron-discharge device comprising an evacuated envelope, a cylinder having longitudinal grooves which forms a portion of said envelope and which acts as an electrode, another electrode cooperating therewith a sheath surrounding said first-named cylinder, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder and said sheath, the distance between the bottom of said longitudinal grooves and the inner surface of the sheath being small compared with the diameter of said cylinder.

2. A cooling system for an electron-discharge device comprising in combination an evacuated envelope, a cylinder having longitudinal ribs thereon, said cylinder forming a portion of said envelope and acting as an electrode, another electrode cooperating therewith, and a cylinder surrounding and spaced away from said firstnamed cylinder, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder, said spacing between said cylinders being so close that the fluid adjacent the surface of said first cylinder moves along the longitudinal axis of the tube at substantially the same velocity as the fluid adjacent the surface of said second cylinder.

3. A cooling system for an electron-discharge 'device comprising in combination an evacuated envelope, a cylinder having longitudinal ribs thereon, said cylinder forming a portion of said envelope and acting as an electrode, another electrode cooperating therewith, a cylinder surrounding and spaced away from said first-named cylinder, said anode being adapted to be cooled by a rapid flow of fluid between said cylinders, the distance between the outer surface of the firstnamed cylinder from which the ribs project and the inner surface of the last-named cylinder being of the order of one-eighth inch and the height of said ribs being substantially one-half of the said distance.

4. A cooling system for an electron-discharge device comprising in combination an evacuated envelope, a cylinder having longitudinal grooves which forms a portion of said envelope and which acts as an electrode, another electrode cooperating therewith, a sheath surrounding said firstnamed cylinder, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder and said sheath, the distance between the bottom of said longitudinal grooves and the inner surface of the sheath being of the order of oneeighth inch.

5. A cooling system for an electron-discharge device comprising in combination an evacuated envelope, a cylinder which forms a portion of said envelope and which acts as an electrode, another electrode cooperating therewith, a sheath surrounding and spaced away from said first-named cylinder, means between said cylinder and sheath forming the space between said cylinder and sheath into longitudinal channels, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder and sheath, the distance between the outer surface of said cylinder and the inner surface of said sheath being short compared to the diameter of said cylinder.

6. A cooling system for an electron-discharge device comprising in combination an evacuated envelope, a cylinder which forms a portion of said envelope and which acts as an electrode, another electrode cooperating therewith, a sheath surrounding said first-named cylinder, means between said cylinder and sheath forming the space between said cylinder and sheath into longitudinal channels, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder and sheath, the distance between the outer surface of said cylinder and the inner surface of said sheath being of the order of one-eighth inch.

7. A cooling system for an electron-discharge device comprising in combination an evacuated envelope, a cylinder which forms a portion of said envelope and which acts as an electrode, another electrode cooperating therewith, a sheath surrounding and spaced away from said first-named cylinder, a plurality of longitudinally aligned spacers disposed to insure against tangential contact between said sheath and said cylinder at either end intermediate the ends thereof, longitudinal channels intervening between said spacers, said anode being adapted to be cooled by a rapid flow of fluid between said cylinder and sheath, the distance between the outer surface of said cylinder and the inner surface of said sheath being short compared to the diameter of said cylinder.

ILIA E. MOUROMTSEFF. GREGORY V. RYLSKY. 

